Celebrities are voicing opposition over Amnesty International— an organization that many had supported.

Human rights group Amnesty International is making a push to legalize prostitution. In response, celebrities have joined 400 others, including prominent faith leaders, in signing a letter from the Coalition Against Trafficking in Women.

"Amnesty's reputation in upholding human rights for every individual would be severely and irreparably tarnished if it adopts a policy that sides with buyers of sex, pimps and other exploiters rather than with the exploited," the letter reads.

Said Taina Bien-Aime, executive director of the coalition: "A prominent human rights organization like Amnesty should be listening to the sex trade victims, women's rights groups and imploring them to not decriminalise the pimps, the brothel owners, and the sex buyers.”

Christian Today reports Amnesty International is scheduled to consider approval of the policy next month. Supporters of the policy say legalizing prostitution means workers can receive better protection and health aid.

"Amnesty International has not made a decision yet on this issue. It is important to stress that given that the consultation process is still on-going, no decisions have been made," Amnesty's Deputy Executive Director Cammie Croft told FOX411.